Microstrip antennas have been widely used because of their advantages over conventional antennas. These advantages include lightweight construction, low cost, and low profile as compared to conventional, bulkier antennas. However, the bandwidth of most microstrip antennas is too narrow for many practical applications. There have been numerous attempts to increase the bandwidth. However, when the operating frequencies are widely separated, even those improved microstrip antennas may not provide sufficient bandwidth. In many applications, such as in the Global Positioning Systems (GPSs), only a few distinct frequency bands are needed rather than a continuous spectrum of operating frequency. Dual-band microstrip antennas have been suggested to meet such requirements. Heretofore, these antennas often have had two independent cavities stacked together or have had vertical conducting connections from the ground plane to the upper patch. However, both of these methods have been difficult to fabricate.